1. Field of the Invention
This invention relates to oxygen curable compositions including mercaptoorganopolysiloxanes, aliphatically unsaturated polydiorganosiloxanes and carboxylic acid salts of metals.
2. Description of the Prior Art
Applicants' U.S. Pat. Nos. 4,039,504 and 4,039,505 are generally directed to compositions curable to elastomers at room temperature or with heat. These compositions are prepared from mixtures of certain polymethylvinylsiloxanes and mercaptoorganopolysiloxanes with an organic peroxide, and optionally a filler.
Applicants' U.S. Pat. No. 4,070,329 discloses compositions prepared from mixtures of mercaptoorganopolysiloxanes, and organic peroxide catalysts. Applicants' U.S. Pat. No. 4,070,328 discloses compositions prepared from mixtures of mercaptoorganopolysiloxanes, organic hydroperoxide, and selected nitrogen compounds. The compositions prepared according to these references can be used as sealants which rapidly cure to elastomers with non-tacky surfaces.
Numerous other prior art references are directed to compositions involving mercaptoorganopolysiloxanes and mixtures thereof with alkenyl-containing siloxanes as well as to curing systems employing electromagnetic and particulate radiation. These references include: U.S. Pat. No. 3,445,419; U.S. Pat. No. 3,816,282; U.S. Pat. No. 3,873,499; German patent publication (OLS) 2,008,426; U.S. Pat. No. 4,064,027; U.S. Pat. No. 4,066,603; and U.S. patent application Ser. No. 663,326, filed Mar. 3, 1976, by Gary N. Bokerman and Robert E. Kalinowski, entitled "Method of Curing Thick Section Elastomers" and assigned to the same assignee as the present invention. The disclosures of the above-identified patents and applications are specifically incorporated by reference herein for the purpose of exemplifying the state of the prior art.
Although the prior art describes elastomeric materials formed by mixing mercaptoorganopolysiloxanes with alkenyl-containing polysiloxanes and organic peroxides, by mixing mercaptoorganopolysiloxanes with organic peroxides alone, or by mixing mercaptoorganopolysiloxanes with organic hydroperoxides and selected nitrogen compounds, it was not expected that useful materials, including elastomeric materials, could be provided by mixing, at room temperature, aliphatically unsaturated polydiorganosiloxanes, mercaptoorganopolysiloxanes and certain metal salts of carboxylic acids. Nor was it expected that these metal salts, when used in mixtures of aliphatically unsaturated polydiorganosiloxanes, mercaptoorganopolysiloxanes and organic peroxides would substantially increase the rate of curing of the mixture to provide elastomeric compositions.